POJ 2299 Ultra-QuickSort
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Ultra-QuickSort
Time Limit: 7000MS | Memory Limit: 65536K | |
Total Submissions: 39767 | Accepted: 14336 |
Description
In this problem, you have to analyze a particular sorting algorithm. The algorithm processes a sequence of n distinct integers by swapping two adjacent sequence elements
until the sequence is sorted in ascending order. For the input sequence
9 1 0 5 4 ,
Ultra-QuickSort produces the output
0 1 4 5 9 .
Your task is to determine how many swap operations Ultra-QuickSort needs to perform in order to sort a given input sequence.
Ultra-QuickSort produces the output
Your task is to determine how many swap operations Ultra-QuickSort needs to perform in order to sort a given input sequence.
Input
The input contains several test cases. Every test case begins with a line that contains a single integer n < 500,000 -- the length of the input sequence. Each of the the following n lines contains a single integer 0 ≤ a[i] ≤ 999,999,999,
the i-th input sequence element. Input is terminated by a sequence of length n = 0. This sequence must not be processed.
Output
For every input sequence, your program prints a single line containing an integer number op, the minimum number of swap operations necessary to sort the given input sequence.
Sample Input
5 9 1 0 5 4 3 1 2 3 0
Sample Output
6 0
归并排序:
#include<iostream> #include<cstring> using namespace std; #define M 500005 int a[M],b[M]; __int64 ans; void mergr_sort(int x,int y) { if(y-x>1) { int m=x+(y-x)/2; //划分 int p=x,q=m,i=x; mergr_sort(x,m); //递归求解 mergr_sort(m,y); //递归求解 while(p<m || q<y) { if(q>=y || (p<m && a[p]<=a[q])) b[i++]=a[p++]; //把左半数组拷贝到暂时空间 else { b[i++]=a[q++]; //把右半数组拷贝到暂时空间 ans+=m-p; } } for(i=x;i<y;i++) a[i]=b[i]; } } int main() { int n; while(cin>>n) { if(n==0) break; memset(a,0,sizeof(a)); memset(b,0,sizeof(b)); int i; for(i=1;i<=n;i++) cin>>a[i]; ans=0; mergr_sort(1,n+1); printf("%I64d\n",ans); } return 0; }
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